%0 Journal Article %T Spectral characterization of Poincar¨¦-Einstein manifolds with infinity of positive Yamabe type %A Colin Guillarmou %A Jie Qing %J Mathematics %D 2009 %I arXiv %X In this paper, we give a sharp spectral characterization of conformally compact Einstein manifolds with conformal infinity of positive Yamabe type in dimension $n+1>3$. More precisely, we prove that the largest real scattering pole of a conformally compact Einstein manifold $(X,g)$ is less than $\ndemi -1$ if and only if the conformal infinity of $(X,g)$ is of positive Yamabe type. If this positivity is satisfied, we also show that the Green function of the fractional conformal Laplacian $P(\alpha)$ on the conformal infinity is non-negative for all $\alpha\in [0, 2]$. %U http://arxiv.org/abs/0909.3207v1